DATASTORE

Problem Statement:

This is a file which can be exposed as a library that supports the basic CRD(create, read, write) operations. Data store is meant to local storage for one single process on single laptop. The datastore is exposed as a library to clients that can instantiate a class and work with the datastore.

Getting Started

To get started with this library, run the npm installer to get all the system requirements and to run the program without any error.
Run the following command:

npm install

After running this command in command shell a node_modules folder will be created which will make run the program without error and in node environment.

File Structure:

As this is a file which is exposed as library so the file structure is kept very simple.

1. datastore.js : This is the main file which will be exposed as library. It has the class which the client can instantiate and all the methods to be used.
2. example.js : This is the file where everything is implemented and demonstrate how the library can be used.
3. package.json and package-lock.json : Setting files for node js

How to run datastore.js:

Whole implementation of datastore.js is demonstrated in example.js. This is a breif summary of running the file as library.

Examples:

1. Initialising class in your example.js

//Importing our datastore file as library
const dataStore = require("./datastore");

//Instantiating the datastore class in our library by creating object for it.
const store = new dataStore();

2. Creating Initial Key Value Pair

store.create("Yatendra", 30000, 60); //Valid Callback
store.create("Pratik", 15000, 30); //Valid Callback
store.create("this sentence is more than 32 chars", 0, 0); //It wont create as the key is not capped under 32 char
store.create("Yatendra", 30000, 60); //Invalid Callback as Yatendra key already exists

3. Reading existing Key Value Pair

console.log(store.read("Yatendra")); //Valid Callback if called before time to live property
console.log(store.read("Pratik")); //Valid Callback if called before time to live property
console.log(store.read("Not Key")); //Invalid as such key doesnt exist

4. Deleting Existing key value pair

store.delete("Pratik"); //Valid Callback if called before time to live property
store.delete("Not Key"); //Invalid as such key doesnt exist

5. Running Example.js and use datastore.js
   After writing all your code in your example.js file, open the command prompt and run -

node example.js